1. Field of the Invention
The present invention relates to a backlight assembly for a liquid crystal display and a liquid crystal display module using the same.
2. Discussion of the Related Art
A liquid crystal display (LCD) device is one of the various flat panel display devices that produce high quality images on the screen. In addition, the LCD devices are thin, light weight, consume lower power, and dissipate lower heat compared to the same screen size Cathode Ray Tubes (CRT). Accordingly, the LCD devices including a plasma display panel device and a field emission display device attract attention as a next generation display device for a wireless phone, a computer monitor, and a television set.
However, the liquid crystal display can be easily damaged by an external impact. Therefore, a liquid crystal display module (LCM) employing a case for protecting the liquid crystal display is used. A typical construction of a related art liquid crystal display module will be described as follows.
FIG. 1 is a sectional view illustrating the related art liquid crystal display module, and FIG. 2 is a plane view illustrating the related art liquid crystal display module. Referring to FIG. 1, the related art liquid crystal display module (LCM) includes a guide panel 17, a backlight unit and a liquid crystal panel 11 mounted on the guide panel 17, a bottom cover 18 for covering a lower surface and a side surface of the guide panel 17, and a top cover 19 for covering a portion of the top edge and side surface of the liquid crystal panel 17. The guide panel 17 is formed using a metal mold and has a jaw-like step part.
A reflecting plate 16, a light guide plate 15, optical sheets 14, and a lamp housing (not shown) are sequentially mounted on the guide panel 17. Polarization plates 12 and 13 are layered on the liquid crystal panel 11, where liquid crystal is injected between upper/lower substrates 11a and 11b. The light guide plate 15 guides light generated from the lamp toward the liquid crystal panel 11. The optical sheets 14 generally include upper/lower diffusion sheets and upper/lower prism sheets. The optical sheets 14 serve to diffuse the light guided from the light guide plate 15, and collect and forward the diffused light in a vertical direction to a front surface of the liquid crystal panel.
The liquid crystal panel 11 has a liquid crystal injected between the lower substrate 11b, having switching elements mounted thereon, and the upper substrate 11a, having a color filter. The lower polarization plate 13 is attached to a lower surface of the liquid crystal panel 11, and polarizes light passing through the optical sheets 14. The upper polarization plate 12 is attached to a front surface of the liquid crystal panel 11, and polarizes light passing through the liquid crystal panel 11. The bottom cover 18 includes a plane part and a side part that bends vertically from the plane part to cover the lower and side surfaces of the guide panel 17. The top cover 19 is provided in a rectangular frame shape and covers an edge and side surfaces of the liquid crystal panel 11.
Accordingly, the reflecting plate 16, the light guide plate 15, the optical sheets 14, and the liquid crystal panel 11 are sequentially mounted on the guide panel 17. A gap (d) is formed between the edge of the liquid crystal panel 11 and the edge of the guide panel 17 because of manufacture tolerances between the respective parts. As shown in FIG. 2, having the gap (d) greatly influences the stability of the liquid crystal panel 11 because the liquid crystal panel 11 can shift. In other words, if the external impact is applied to the liquid crystal display module, the liquid crystal panel 11 shifts in the gap (d) formed between the liquid crystal panel 11 and the guide panel 17. Thus, this shifting causes a friction between the surfaces of the liquid crystal panel 11 and the guide panel 17.
In addition, since the guide panel 17 is constructed using a mold, the friction generates a foreign material. Specifically, the friction is formed between the lower polarization plate 13 attached to the liquid crystal panel 11 and the optical sheets 14 facing the lower polarization plate 13, thereby causing a noise. Furthermore, light passing through the optical sheets 14 does not get forwarded to the liquid crystal panel 11 in the vertical direction, thus creating a white stain and greatly deteriorating a picture quality.